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Continuous flow‐driven inversion for arterial spin labeling using pulsed radio frequency and gradient fields
Author(s) -
Dai Weiying,
Garcia Dairon,
de Bazelaire Cedric,
Alsop David C.
Publication year - 2008
Publication title -
magnetic resonance in medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.696
H-Index - 225
eISSN - 1522-2594
pISSN - 0740-3194
DOI - 10.1002/mrm.21790
Subject(s) - continuous wave , arterial spin labeling , nuclear magnetic resonance , duty cycle , radio frequency , materials science , computer science , biomedical engineering , perfusion , physics , optics , medicine , telecommunications , radiology , laser , power (physics) , quantum mechanics
Abstract Continuous labeling by flow‐driven adiabatic inversion is advantageous for arterial spin labeling (ASL) perfusion studies, but details of the implementation, including inefficiency, magnetization transfer, and limited support for continuous‐mode operation on clinical scanners, have restricted the benefits of this approach. Here a new approach to continuous labeling that employs rapidly repeated gradient and radio frequency (RF) pulses to achieve continuous labeling with high efficiency is characterized. The theoretical underpinnings, numerical simulations, and in vivo implementation of this pulsed continuous ASL (PCASL) method are described. In vivo PCASL labeling efficiency of 96% relative to continuous labeling with comparable labeling parameters far exceeded the 33% duty cycle of the PCASL RF pulses. Imaging at 3T with body coil transmission was readily achieved. This technique should help to realize the benefits of continuous labeling in clinical imagers. Magn Reson Med 60:1488–1497, 2008. © 2008 Wiley‐Liss, Inc.